Ultrasensitive spectrometer

Abstract

Provided is an ultrasensitive spectrometer. The ultrasensitive spectrometer includes a scattering medium, a light-receiving sensor disposed at a rear end of the scattering medium, a storage unit storing previously predicted speckle pattern information according to wavelengths with respect to the scattering medium, and a signal processing unit configured to process a sensing signal generated by the light-receiving sensor. The scattering medium scatters incident analyzing light to form a random speckle pattern, and the light-receiving sensor senses the speckle pattern formed by the scattering medium. The signal processing unit restores spectrum information of the analyzing light from sensing information sensed of the speckle pattern formed by the scattering medium.

What is claimed is: 
     
         1 . An ultrasensitive spectrometer comprising:
 a scattering medium configured to scatter incident analyzing light to form a random speckle pattern that sensitively changes according to wavelength variations;   a light-receiving sensor disposed at a rear end of the scattering medium and configured to sense the speckle pattern formed by the scattering medium;   a storage unit comprising a memory storing previously predicted speckle pattern information according to wavelengths with respect to the scattering medium; and   a signal processing unit comprising a processor configured to process a sensing signal generated by the light-receiving sensor to restore spectrum information of the analyzing light from sensing information of the speckle pattern formed by the scattering medium,   wherein at least one of a number of a plurality of metasurfaces of the scattering medium and a separation distance between the plurality of metasurfaces is determined such that speckle sizes of at least some of speckles of the speckle pattern are greater than a pixel size of the light-receiving sensor, and   wherein a degree of disorder of the plurality of metasurfaces is constrained such that an average speckle size of the speckle pattern is greater than the pixel size of the light-receiving sensor.   
     
     
         2 . The ultrasensitive spectrometer of  claim 1 , wherein at least one condition among scattering characteristics of the scattering medium and a separation distance between the scattering medium and the light-receiving sensor is determined such that a speckle size of at least some of speckles of the speckle pattern formed on a sensing surface of the light-receiving sensor are greater than the pixel size of the light-receiving sensor. 
     
     
         3 . The ultrasensitive spectrometer of  claim 2 , wherein the at least one condition is determined such that an average speckle size of the speckle pattern is greater than the pixel size of the light-receiving sensor. 
     
     
         4 . The ultrasensitive spectrometer of  claim 1 , wherein the signal processing unit is further configured to restore the spectrum information by applying a compressive sensing algorithm to the sensing information of the speckle pattern. 
     
     
         5 . The ultrasensitive spectrometer of  claim 4 , wherein the signal processing unit is further configured to restore the spectrum information of the analyzing light through an inverse operation process that sensing information of an overlapped speckle pattern represents as a matrix operation of a compressive sensing response matrix obtained using the previously predicted speckle pattern information stored in the storage unit and an input spectrum. 
     
     
         6 . The ultrasensitive spectrometer of  claim 1 , wherein the scattering medium comprises a transparent medium and nanoparticles disorderly dispersed in the transparent medium. 
     
     
         7 . The ultrasensitive spectrometer of  claim 6 , wherein the nanoparticles comprise a plurality of nanoparticles having different sizes, and
 a size range of the nanoparticles is determined to obtain spectral characteristics in a set spectral range.   
     
     
         8 . The ultrasensitive spectrometer of  claim 6 , wherein the transparent medium is transparent to visible light. 
     
     
         9 . The ultrasensitive spectrometer of  claim 6 , wherein the transparent medium comprises polydimethylsiloxane (PDMS), and
 the nanoparticles comprise ZnO.   
     
     
         10 . The ultrasensitive spectrometer of  claim 6 , wherein the scattering medium is single layered or is formed by stacking a plurality of scattering medium layers. 
     
     
         11 . The ultrasensitive spectrometer of  claim 6 , wherein a thickness and a scattering coefficient of the scattering medium are limited to obtain a set spectral resolution. 
     
     
         12 . The ultrasensitive spectrometer of  claim 11 , wherein the thickness and the scattering coefficient of the scattering medium are limited to obtain a spectral resolution of 0.1 nm or less. 
     
     
         13 . The ultrasensitive spectrometer of  claim 1 , wherein the scattering medium comprises a stacked structure of the plurality of metasurfaces that are spaced apart from each other and each have an array of meta-atoms, and
 at least one of the plurality of metasurfaces is a random metasurface.   
     
     
         14 . The ultrasensitive spectrometer of  claim 13 , wherein the random metasurface comprises meta-atoms arranged in a disordered size distribution. 
     
     
         15 . The ultrasensitive spectrometer of  claim 14 , wherein the meta-atoms of the random metasurface are formed at an identical height and sizes of the meta-atoms are irregular. 
     
     
         16 . The ultrasensitive spectrometer of  claim 15 , wherein the meta-atoms of the random metasurface are regularly positioned. 
     
     
         17 . The ultrasensitive spectrometer of  claim 14 , wherein the meta-atoms of the random metasurface are regularly positioned and have irregular sizes. 
     
     
         18 . The ultrasensitive spectrometer of  claim 13 , wherein the separation distance between the plurality of metasurfaces is limited to obtain a spectral resolution of 0.1 nm or less.